Direct-lift aircraft



May 4, 1943.

l. l. SIKORSKY 2,318,259

DIRECT-LIFT AIRCRAFT Filed April 6, 1940 10 Sheets-Sheet 1 w (2 myzmona: :8 aYlgarlfiilgarsliy 2 N 1414/ i L N ATTORNEY May 4, 1943. l. l.SIKORSKY DIRECT-LIFT AIRCRAFT Filed April 6, 1940 10 Sheets-Sheet 2 SUNmvENTo [garlfizkursb f m 2 ATTOR'NEY y 1943- l. SIKORSKY 2,318,259

DIRECT-LIFT AIRCRAFT Filed April 6, 1940 10 Sheets-Sheet 3 INVENTOR l[5201"]. fikarsl y ATTORNEY May 4, 1943- l. I. SIKORSKY DIRECT-LIFTAIRCRAFT Filed April 6, 1940 10 Sheets-Sheet 4 mmw,

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ATTORNEY May 4, 1943. l. l. SIKORSKY DIRECT-LIFT AIRCRAFT Filed April 6,1940 10 Sheets-Sheet l0 INVENTOR qwlfikars ATTORNEY Patented May 4, 1943nmao'r-m r amoam I Igor U I. Sikorlb', Trumbull, Com. assignor to nitedAircraft Corporation, East Hartford,

Conn., a corporation of Delaware Application April 6, 1940, Serial No.328,225

This invention relates to improvements in aircraft and hasparticularreference to improvements in direct lift type of aircraftcommonly referred to as helicopters.

'An object of the invention resides in the provision of an improveddirect lift type aircraft of the character indicated, having an engine,or engines, a main rotor and auxiliary rotors or propellers with apositive driving connection between the main rotor and the auxiliaryrotors and an automatic one-way driving connection between the engineand the rotors.

A further object resides in the provision, in a direct lift typeaircraft of the character indicated having an engine, or engines, a mainrotor and means for changing the pitch of the main rotor, of means forautomatically controlling the engine power as the pitch of the mainrotor is changed in order to avoid stalling the engine or reducing itsspeed to a dangerously low value when the pitch is increased as well aspreventing the engine and rotor from increasing excessively the speed ofrotation when the pitch is suddenly decreased.

A still further object resides in the provision, in a direct type liftaircraft of the character indicated having an adjustable pitch, enginedriven, main rotor, of means for adjusting the pitch of the main rotorand additional foot operated means for temporarily decreasing the mainrotor pitch to facilitate maneuvering of the aircraft.

An additional object resides in the provision in a direct lift aircrafthaving an engine or engines, a main lifting rotor and one or moreauxiliary lifting rotors. of means for automatically controlling thepitch of the auxiliary lifting rotors when the pitch of the main rotoris manually or automatically changed to prevent the machine from losingits normal position, the manual control of the auxiliary rotors beingretained so that the position of the machine can be manually controlledduring the operation of said automatic control.

Another object resides in the provision, in a direct lift aircrafthaving an engine or engines, a main lifting rotor and one or moreauxiliary lifting rotors, of means for automatically controlling theengine power as the pitch of the main lifting rotor and the auxiliarylifting rotors is changed in order to prevent stalling the engine orreducing its speed to an undesirably low value, as well as to preventthe engine from increasing its speed to an undesirably high value.

Still another object resides in the provision in a direct lift typeaircraft of the character indi cated having an engine and a main rotor,of auxiliary rotors disposed in two intersecting planes to each other toprovide manual control in at least two directions.

Other objects and advantages will be more particularly pointed outhereinafter or will become apparent as the description proceeds.

In the accompanying drawings, in which like reference numerals are usedto designate similar parts throughout, there is illustrated, by way ofexample, a, suitable mechanical embodiment for the purpose of disclosingthe invention and two slightly modified forms of a particular part ofthe apparatus. The drawings, however, are for the purpose ofillustration only and are not to be taken as limiting the invention asit will be apparent to those skilled in the art that various changes inthe illustrated construction may be resorted to without in any wayexceeding the scope of the invention.

In the drawings,

Fig. 1 is a side-elevational view of an aircraft constructed accordingto the invention.

Fig. 2 is a rear-elevational view of the aircraft illustrated in Fig. 1on a somewhat enlarged scale, the rear propeller and support thereforbeing omitted for purposes of clarifying the illustration.

Fig. 3 is a top plan view, on a somewhat enlarged scale, of the aircraftillustrated in Fig. 1, the main supporting rotor being omitted for thepurpose of clarifying the illustration.

Fig. 4 is a side-elevational view, on an enlarged scale, of the forwardportion of the aircraft illustrated in Fig. 1, the rearportion of theaircraft and the landing gear being omitted.

Fig. 5 is a plan view on an enlarged scale of the means for mounting theblades of the main rotor.

Fig. 6 is an elevational view of a bracket for connecting pitchcontrolling members to a main rotor blade.

Fig. 7 is a partly sectioned elevational view of the main rotor bladesupporting and pitch controlling means.

Fig. 8 is a plan view of the mechanism for varying the pitch of the mainrotor blades.

Fig. 9 is a plan view of the auxiliary rotor and operating mechanismtherefor including a portion of the automatic direct control.

Fig. 10 is a view of a fragmentary portion of the mechanism shown inFig. 9 taken at an angle ninety degrees to the position shown in Fig. 9and particularly illustrating the means for controlling the blade pitchof the auxiliary rotor.

Fig. 11 is a plan view of a somewhat diiferent form of auxiliary-rotor,and 1 18.12 is a transverse sectional view on an enlarged scale of thedriving connection between the engine and the rotors and between themain rotor and auxiliary rotors.

Referring to the drawings in'detail, and particularly to Fig. 1, theaircraft comprises a fuselage. generally indicated by the numeral I0,composed of various structural members such as the welded tubesindicated at I2 and I4, some of which will be referred to in detaillater on, an, engine I6, a main supporting rotor I8, a tail structure20, a stabilizing and directional control auxiliary rotor 22, a landinggear including the wheels 24, 26 and 26, a pilot seat 30 and-a number ofpower transmitting and control instrumentalities which willbe referredto in detail as the description proceeds.

The landing gear may include the two lateral wheels 24 and 26, the rearwheel 28, and a front wheel 26, all of said wheels preferably havingswivel connections with the respective shock members 62, 34, 36 and 31which are secured to the fuselage I by suitable frame members.

The engine I6 is preferably mounted in the lower portion of the fuselagebeneath the main rotor where its weight will be of assistance inmaintaining the aircraft in proper upright position during flight andmay be connected by suitable means, such as the pulleys 36 and 40 andbelt drive 42, or other type of drive, with the main rotor I6 andauxiliary rotor 22.

As is particularly shown in Fig. 12, the pulley 40 has an outer portion43 and a concentric inner portion 44 which two portions are rotatablerelative to each other in one direction but are drivingly connected inthe opposite direction by the one-way clutch 46. The inner portion 44 isfixed on one end of a shaft 48 which may be supported in a casing 60 bythe spaced antifriction bearings 62 and 54. The end of the shaft 46projects into a housing 66 and i provided with a beveled gear 66 whichmeshes with a large beveled gear 60 fixed on the lower end of a tubularshaft 62 the upper end of which is drivingly connected .with the hub ofthe main rotor I8. The inner portion 44 of the pulley 40 is connectedthrough suitable means, such as the flexible coupling generallyindicated at 64, with a shaft 66 which extends along the tail structure20 to a gear box 66 located near the rear end of the tail structure 20and particularly illustrated in Figs. 9 and 10. The boom or tailstructure 20 is preferably made up of structural members which give it agenerally hollow construction and the shaft 66 extends through thehollow interior of the tail structure andis supported therein bysuitable means such as the bearings I0.

As is particularly shown in Fig. 9, the shaft 66 is provided within thegear box 68 with a beveled gear I2 which meshes with a beveled gear I4on the end of a hollow drive sleeve 16 which carries at its opposite endthe auxiliary rotor or propeller blade I8. With this arrangement the tworotors I6 and 22 will always rotate together but both may rotateindependently of the engine I6 since, if the engine speed decreases to avalue below the rotor speed the one-way clutch 46 will permit the rotorsto automatically overrun the engine and will drivingly connect theengine with the rotors when the engine speed equals the speed of therotors.

As shown in Figs. 1, 3, 4 and 12 the gear casing 66 may be in the formof a parallelogram and may be rigidly secured to the fuselage I0 bysuitable vertical structural members, as indicated at I4, 80, 82 and 84,which members are connected at their ends by cross members 68 and 60 andsuitably braced by various diagonal members such as 92 and 94 as clearlyindicated in the accompanying drawings. Since the gear case 66 issmaller than the space included between the four upright members I4, 60,62 and 64 it may conveniently be secured to two of the upper crossmembers, as indicated at 08 and 90, and may be braced in position bysuitable diagonal members, as indicated at 92 and 64 in Fig. 2. Theabove construction provides a rigid fuselage for supporting the engineI6 and the gear casing 66 in spaced relation with respect to each otherand for resisting the various stresses imposed on the structure duringflight.

A vertical sleeve member 96 extends upwardly from the top of the gearcasing 66 and the shaft 62 is rotatably supported in this sleeve memberby suitable means such as the tapered roller bearings 98 and I00 whichrestrain the shaft 62 against lengthwise movement relative to the sleeve96 while permitting free rotation of the shaft.

Above the sleeve 96 the shaft 62 carries the main rotor hub generallyindicated at I02 in Fig. l and particularly illustrated in Figs. 5 and7. A triangular bracket member I04 is rigidly secured to the upper endof theshaft 62 and provided with pairs of apertured lugs which receivethe hinge bolts I06, I08, and III! by means of which the hinge butts H2,H4 and H6 are pivotally secured to the bracket member I04. The axes ofthe pins I06, I08 and H0 are substantially at right angles to the axisof the shaft 62 so that the butt plates H2, H4 and H6 may swing up anddown and change their angle with respect to the axis of the shaft 62.The rotor blades, one of which is indicated at, H8 in Fig. 5, aresecured to the free ends of the respective plates H2, H4 and H6, bymeans of vertical pivots as indicated at I20, I22 and I24 so that theblades may swing relative to the hub structure in the plane of rotationof the rotor and the blades are also mounted at their inner ends inlongitudinally disposed pivotal connections each comprising a stub shaftI25 connected at one end to the pivot I20 and extending through spacedradial bearings I21 and I29 and a thrust bearing iii all secured in theblade end structure and retained in position in these bearings by asuitable abutment such as is constituted by the nuts I33 and I35 screwthreaded onto the end of the stub shaft and bearing against the thrustbearing I3 I These bearings are preferably anti-friction bearings andthe bearings I21 and I28 may desirably be pin roller type bearings inorder to provide adequate load carrying capacity and save weight andspace, the construction being such that the blades may turn in pitchchanging directions. This construction provides a substantiallyuniversal joint connection between each blade and the rotor hub so thatthe blades may swing up and down under the influence of centrifugal andaerodynamic forces and may swing in the plane of rotation of the rotorto avoid sudden movements or whipping in case there is any unevenness inthe rotation of the hub. The blades are constrained to rotate with thehub by means of the flexible connections, one of which is particularlyillustrated in Fig. 5 and which in- .the hinge points I62,

eludes the pivoted link member I26 which slidably extends through asleeve I28 secured intermediat its length to a bracket I88 fastened ontothe trailing edge of the rotor blade II8, rubber cushions I82 and I84being disposed between the opposite ends of the sleeve and abutments inthe form of pairs of adjustable nuts I86 and I58 screw threaded onto thelink I26. A bracket member I48 is pivotally secured to the leading edgeof each blade by means of a vertical pivot I42 passing through alignedapertures in the projecting ends of a pair of strap members I44 and I46(see Fig. 6) secured one to the upper and one to the lower surface ofthe blade adjacent the inner end thereof and projecting somewhat beyondthe blades toward the respective blade carrying butt plates. Eachbracket may comprise a tubular member I48 of a length slightly greaterthan the thickness of the rotor blades having secured to each endthereof a plate provided with an apertured extension receiving the pivotpin I42. At its side opposite the pivot I42 the bracket carries a pairof vertically spaced ball joint members I58 and I52. The upper balljoint member I52 is connected by means of a pivoted link I54 with theadjacent end of the respective pivot pin I86, I88 or H8, and the lowerball joint I58 is connected by means of a pivoted link 56 with a rotorpitch adjusting member particularly illustrated in Figs. 7 and 8 andgenerally indi cated at I58. It is to be understood that a bracket, asindicated at I48, is pivotally connected to the leading edge portion ofthe inner end of each rotor blade and is in turn pivotally connected bymeans of links I55 I54, with the adjacent end of the respective buttplate hinge pin and that the lower ball joints of these various bracketmembers are connected by the respective pivoted links I56, I59 and I68(see Fig. 8) with angularly spaced hinge points I62, I64 and I66 on thepitch adjusting member I58.

The member I58 may comprise a flat plate I68 having an aperture I18which surrounds the shaft 62 above the upper end of the vertical sleeve96. Around the aperture I18 a cylindrical collar I12 is secured to theupper side of the plate I68 and carries at its upper end a ball bearingI14 the outer race of which is attached to a flat plate I16 whichcarries the hinge points I62, I64 and I66. This construction permits theplate I16, I64 and I66 and the link I68 to rotate with the rotor I8 andrelative to the plate I68, the bearing I14 being a thrust type bearingso that pitch controlling movements of the member I58 are transmitted tothe plate I16 and hence to the rotor members I56, I59 and and I51,similar to the link one end of a manually operable lever I92 which ispivoted intermediate its length to the framework of the fuselage I8, asindicated at I94.

It will be apparent that movements of the lever I92 will act through theintermediacy of the link I98, arm I88, shaft I86, arms I82 and I84, andlinks I18 and I88 to move the pitch adjusting member I58 up and downrelative to the rotor hub I82. Such up and down movements of the memberI58 will act through the pivoted links I56, I59 and I68 to rotate'theblades about the respective stub shafts one of which is indicated at Iin Fig. 5, the upper pivoted links I54, I and I51 serving as reactionmembers to cause the corresponding links I56, I59 and I68 to rotate theblades about the respective blade attaching stub shafts instead of aboutthe vertical pivots I28, I22 and I24.

As is particularly shown is pivotally mounted intermediate its length onthe lower portion of the link I98 and has one end connected with theactuating arm 284 of the engine throttle and its opposite end connectedwith a pivoted manually operable bell-crank lever 286 mounted on theframe adjacent to the pilot seat 38. This arrangement is such that thethrottle may be manually adjusted by the lever 286 and will also beautomatically adjusted by movement of the link I98 to increase theblades through the linkag system described above. One of the linksconnecting the plate I16 with the rotor, for example, the link I56, maybe formed as a structural member having spaced hinge points connectedwith the plate and a torsionally rigid construction to keep the plateI16 in a predetermined angular position relative to the rotor I8 duringrotation of the rotor and the plate.

The pitch controlling member I58 is supported on a pair of verticalmembers I18 and I88 each of which is pivotally connected at its upperend to the underside of the plate I68 and pivotally connected at itslower end to the ends of respective arms I82 and I84 (see Fig. 4)projecting outwardly from a rotatable shaft I86 supported in suitablebrackets above the gear case 56 and having at one end a third outwardlyprojecting arm I88 connected by a suitable link I98 with power of theengine I6 whenever the pitch of the rotor blades is increased, and tocorrespondingly decrease the engine power when the rotor pitch isdecreased.

The manual pitch control lever I92 operates in a quadrant 288 whichretains it in the position to which it is manually adjusted. Thisquadrant is held in position by a flexible device including a link 2I8and a spring 2I2 and is connected by suitable means such as the flexiblecable 2 with a foot pedal 2I6. This cable may be led over a pulley orsheave 2I8 to give the proper direction of pull on the quadrant 288.With this arrangement if the pedal 2I6 is manually depressed the pitchof the rotor I8 will be decreased and the lift of the aircraft will bediminished. This control materially facilitates landing the aircraft andmaneuvering it when near the ground. When the rotor pitch is thusdecreased the lever 282 will be moved to simultaneously decrease theengine power to avoid overrevving of the engine and rotor and insure asubstantial decrease in the lift of the aircraft. In order to obtainsatisfactory control in flight it may be desirable to periodically varythe lift of the main rotor both fore and aft and laterally. Thus, inorder to obtain the proper pitching control, the main rot-or lift may bedecreased forwardly and increased rearwardly or vice versa and to obtainlateral control the lift may be increased on one side and decreased onthe other and this variation in lift may be reversed from one side tothe other as may be necessary in order to maintain the aircraft inproper equilibrium. This variable or periodic change in rotor lift maybe obtained by moving the pitch control member I58 laterally relative tothe shaft 62 and proper instrumentalities are provided to give to thispitch control member both a fore and aft movement and a lateral movementas will presently appear. A manual control column 228 is mounted on ashaft 222 near one end thereof in such a manner that the control columnmay pivot forwardly and rearwardly relative to the longitudinallydisposed shaft but when moved laterally will rotate the shaft 222. Alink 224 subin Fig. 4, a lever 282 stantially parallel to the shaft 222is pivoted to the control column 228 at a point 228 spaced from thecontrol column pivot 228 and is pivotally connected at its end oppositethe control column to one leg of a pivoted bell-crank lever 238 theother leg of which is pivotally connected to a vertical link 232 theupper end of which is pivotally connected to the apex of a triangleincluding the link members 234 and 238 of which the member 238 ispivotally connected at its opposite end to the gear case 58 and themember 234 is pivotally connected at its. opposite end to the forwardside of the pitch changing mem ber I58. The manual control column 228 inmoving fore and aft will move the link 232 up and down swinging the link238 about its pivotal connection with the fixed gear case 58 and therebymoving the link 234 and the pitch control member I58 in a fore and aftdirection. When the member I58 is moved forwardly the plate I18 willalso be moved forwardly thereby pushing up on the pivoted links I58, I58and I88 as these links reach their forward position and pullingdownwardly on the links as they reach their rearward position. Thisaction will increase the rotor lift at the front and decrease the liftat the rear of the rotor and tend to force the nose of the aircraftupwardly as would be expected from a rearward movement of the controlcolumn. A forward movement of the control column would correspondinglyincrease the lift at the rear of the rotor and decrease the lift at thefront thereby forcing the nose of the aircraft down in the conventionalmanner.

The shaft 222 carries at its rear end a cross lever 238 the oppositeends of which are connected by the cables 248 and 242 with the oppositeends of a cross lever 244 fixed on the lower end of a shaft 248 (seeFig. 2) which is pivotally mounted on the gear case 58 by suitablemeans, such as the brackets one of which is indicated at 248, the cablesbeing led over suitable pulleys or sheaves 258 and 252 (see Fig. 3), togive the proper direction of pull on the lever 244. At its upper end theshaft 248 carries a lever arm 254 the free end of which is connected bymeans of a suitable link 258 with the adjacent side of the pitch controlmember I58. With the above described arrangement, movement of thecontrol column 228 from side to side will rotate the shafts 222 and 248and thereby move the pitch control member I58 to change the lift of themain rotor from one side of the aircraft to the other to control therolling movements of the aircraft.

As mentioned above, the directional movements of the aircraft arecontrolled by the auxiliary rotor 22 the control being obtained bychanging or reversing the pitch of the blade 258 of the auxiliary rotor.For this purpose a pair of cables 288 and 282 may be connected to thefoot pedals 284 and 288 respectively and to the opposite ends of a leverbar 288 pivotally mounted intermediate its length on the gear box 88 insuch a manner that movement of the pedals 284 and 288 will swing thelever bar 288 about its pivotal connection. A lever arm 218 movable withthe bar 288 projects rearwardly therefrom and is connected by means of alink 212 with the projecting end of a rod 214 which extends through thehollow rotor drive sleeve 18 and through the rotor and has itsprojecting end connected by means of a pivoted link 218 with a bracket218 secured to the leading edge of the rotor blade 258 in such a mannerthat lengthwise movement of the rod 214 will turn the blade 258 aboutits longitudinal axis to change the pitch of the blade the blade beingpivotally connected intermediate its width to the drive shaft by atrunnion as indicated at 258. With this arrangement the pilot cancontrol the direction in which the aircraft is pointed by moving thefoot pedals 254 and 254 to vary the pitch of the secondary rotor blade18, the thrust of this blade being applied to the tail structure 28 in amanner to swing the aircraft about the rotational axis of the mainrotor. In order to obtain automatic directional stability the vane 288disposed rearwardly of the rotor 22 may be connected to the arm 218 by asuitable support in the form of a tubular member 282 which support mayalso be connected to an arm 283 pivoted on the opposite side of the gearbox from the arm 218 and connected with the end of the rod 214 by a link285 substantially parallel to the link 212. This arrangement is suchthat any lateral air force acting on one side or the other of vane 288will move the vane sideways and swing the member 282 and arm 218 to movethe shaft 214 and change the pitch of the rotor blade 18. If desired,the vane 288 may be connected to the member 282 by means of anadjustable connection, generally indicated at 284, so arranged that thevane may be set at the proper angle to compensate the torque of the mainrotor and the air whirl caused by operation of the main rotor.

Additional directional control and damping of the movements of theaircraft about the axis of the main rotor may be provided by increasingthe vertical dimension of the tail structure or by attaching to the tailstructure a fixed vertical fin as indicated at 281 in Fig. 1.

If desired the aircraft may be equipped with a fuel tank 288 asparticularly shown in Fig. 2, an oil tank, not illustrated, an idlerpulley 288 for tightening the belt 42 and other equipment as may benecessary or desired, the essential operating and control features onlyhaving been particularly illustrated in the drawings and hereinabovedescribed.

In the. arrangement shown in Fig. 11, the shaft 88 is connected by auniversal connection 324 with a stub shaft 328 which projects into oneportion 328 of a two part gear box generally indicated at 338 which isthe equivalent of the gear box 88 shown in Figs. 3 and 9. The stub shaftis supported in the gear box by the spaced antifriction bearings 332 and334 which ma conveniently be retained in operative position by the screwcaps 338 and 338, and carries the bevel gear 12 which meshes with thegear 14 of Fig. 9 on the inner end of the drive shaft 18 of the rotor22. Otherwise the construction of the rotor 22 and its control is thesame as that illustrated in Fig. 9 and described above. The gear 14 alsomeshes with a beveled gear 348 on the inner end of a vertically disposeddrive shaft 342 which carries on its upper end a rotor blade 344. Thedrive shaft 342 is supported in anti-friction bearings 348 and 348 in asecond portion 358 of the gear box 338, these bearings being held inoperative position by suitable means such as the spacer 352 and glandnut 354 which also compresses a packing seal 358 about the shaft 342where it projects from the gear box. The part 358 of the gear box is sodisposed relative to the part 328 that the shaft 342 inclines somewhatforwardly relative to.the shaft 328 in order that the gear 348, whilemeshing with the gear 14, will clear the gear 12. The pitch of thehorizontal rotor blade 344 carried by the vertical shaft 342 may becontrolled by suitable means such as the sleeve 3" slidable on the shaft342 between the gear box and the rotor blade pivotally connected to theleading edge of the blade by suitable means including the pivoted linkI" and provided with an annular groove "2 which receives the points of ayoke member I pivotally mounted on a bracket 3" and having connectedthereto a control link 36!.

With this arrangement the rotor blade ll provides directional controlfor the aircraft, as described above, and the rotor blades 3 providespitching control either exclusively or in addition to the pitchingcontrol provided by the main rotor and also serves to provide a portionof the lift necessary to support theaircraft in the air.

The blades are so disposed that, while the rotational planes of the twoblades intersect substantially at right angles, the blades pass throughthe location of intersection of the two planes at different times andthere is, therefore, no interference between the blade during operation.

While a particular mechanical embodiment and two somewhat modifieddetails thereof have been hereinabove described and illustrated in theaccompanying drawings for the purpose of disclosing the invention, it isto be understood that the invention is not limited to the particularconstruction so illustrated and described but that such changes in thesize, shape and arrangement of the various parts may be resorted to ascome main rotor for controlling the pitch of said auxiliary rotor tominimize such movements.

5. In an aircraft having a main sustainins rotor including a pluralityof airfoil blades, and a rotor supporting drive shaft, a universalconnection between the inner end of each blade and said shaft, a pivotalconnection between each blade and said shaft providing freedom of pitchchanging movements of said blades about their longitudinal axes, abracket pivotally connected to the inner end of each blade on an axisperpendicular to said longitudinal axis, a pitch control membersurrounding said shaft at a location spaced from said universalconnections, a pair of rigid links pivotally connected to each bracketat locations spaced apart in the direction of the thickness of saidblade and spaced from the major axis thereof, a pivotal connectionbetween one of said links and said shaft, and a pivotal connectionbetween the other of said links and said control member.

6. The arrangement as set forth in claim 5 in which the pivotalconnection between one of said links and said control member is a torquetransmitting connection operative to constrain a portion of said controlmember to rotate with said rotor.

7. The arrangement as set forth in claim 5 including resilient torquetransmitting links pivotally secured to said blades and said shaft toconstrain said blades to rotate with said shaft while permitting alimited freedom of resiliently resisted movement in the plane ofrotation about said motor for simultaneously and positively varying therotor pitch and the-power output ofsaid engine upon each movcment ofsaid manually actuatable means.

2. In an aircraft having a direct lift main rotor and an auxiliary rotorhaving a plane of rotation at right angles to the plane of rotation ofsaid main rotor, an auxiliary rotor blade mounted for pitch changingmovements, means for changing the pitch of said blade, and meansresponsive to positional changes of said aircraft operatively connectedwith said pitch changing means for controlling the pitch of saidauxiliary rotor to maintain the position of said aircraft substantiallyconstant.

3. In an aircraft having a direct lift main rotor and an auxiliary rotorfor directional control, means for changing the pitch of said auxiliaryrotor, and a vane responsive to movements of said aircraft about theaxis of said main rotor for automatically controlling the pitch of saidauxiliary rotor to control rotational movements of said aircraft aboutsaid axis.

4. In an aircraft having a. direct lift main rotor and an auxiliaryrotor for changing the position of'said aircraft about the axis of saidmain rotor, means for varying the effect of said auxiliary rotor bychanging the pitch thereof, operator actuated means for controlling saidpitch changing means. and means responsive to movements of said aircraftabout the axis of said said universal Joints.

8. In an aircraft having a. direct lift main rotor, a combination of twoauxiliary rotors arranged so closely to each other as to intersect theplane ofrotation of each other, spaced from said main rotor and eachhaving one or'more blades, the rotors in said combination being disposedapproximately at right angles to each other. one of said auxiliaryrotors being effective to control turning movement of said aircraftabout the axis of the main rotor and the other being effective to changethe plane of rotation of said main rotor, means for driving saidcombination of auxiliary rotors from said main rotor. means forindependently changing the pitch of each of said auxiliary rotor blades,and operator actuated means for controlling said pitch changing means.

9. In an aircraft having a direct lift rotor and an engine for drivingsaid rotor, means connected with said rotor for varying the pitchthereof, a throttle for said engine, and mechanism positively andpermanently connecting said throttle with said means, said mechanismincluding means for selectively setting the throttle at will and meansactuated by each pitch changing movement of said pitch varying means,for simultaneously, positively, varying said selected throttle setting.

10. In an aircraft having a direct lift rotor and an engine for drivingsaid rotor, means connected with said rotor for varying the pitchthereof, a throttle control for said engine, means for setting saidthrottle at any desired position, means positively and permanentlyconnecting said throttle control with said pitch varying means forsimultaneously and positively varying the rotor pitch and the poweroutput of said engine upon each movement of said pitch varying means.

IGOR I. BIKORSKY.

